FM receiver

[zachtheterrible]

:lol: that was funny audio :lol: i cant stop laughing :lol:

ahem, so what do i do? should i just finish reading my ARRL handbook and then be able to figure it out myself?

 

[Nigel Goodwin]

SO WHAT DO I DO!?!? I do NOT want to make a better transmitter, I simply want to be able to hear my transmitter from farther away with a more sensitive radio. It seems that we've been going around in circles!

You're really wanting something which is probably unattainable, the limiting factor at VHF is the noise of the front end of the receiver, at lower frequencies it's limited by external noise.

This means that the possible increases available in the receiver are limited, if your receiver is already a decent superhet one you probably can't improve it massively.

Your biggest improvement is likely to come from a decent aerial system, a large beam (yagi) feeding the receiver will increase range a fair bit, you should use a GOOD quality FM (HiFi component) receiver - you can probably still get good quality seperates.

But basically, as you already know?, you need to increase transmitter power!.

 

[zachtheterrible]

That's what I needed to hear Nigel, if this is attainable or not!

I guess I just need to keep studying up and eventually, somehow work this out.

 

[mstechca]

SO WHAT DO I DO!?!?

Two tin cans connected with a tight string.

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAAAAA! NO
That is one of the most ridiculous methods I have seen for a transmitter.

Hi Zach,
Things wrong with a super-regen radio:
1) Its selectivity is terrible because a super-regen has just a single tuned circuit. It is also overloaded easily by stations it is not tuned to. A real radio has many tuned circuits.

"terrible" is defined by the capacitor between the base and emitter of the transistor. A single tuned circuit is a heck of a lot better because 1) it is more compact, and if I'm lucky, 2) I could probably add some logic to it so that superregens can be electronically switched, rather than turning a dial.

2) Its noise level is high and it overloads easily by the station it is tuned to because it is oscillating all the time (quenched, in bursts).

What are the chances that people would want to hear a station no one is transmitting on?
and if he is doing a transmitter, its all the better, because when the transmitter starts, the receiver can then pick up the transmitter well, and the noise drops.

3) The bandwidth is too narrow for proper FM broadcast reception, with lots of distortion, because it "amplifies" with positive feedback instead of gain.

this is when the capacitors have to be played with.

4) It doesn't even have an FM detector. It is basically an AM radio that detects the amplitude change of the changing frequencies of an FM signal when the station is tuned to the slope of its tuned circuit. Therefore it is more sensitive to AM interference (tuned at the peak) and less sensitive to FM (tuned to one side).

How's an antenna for a detector? LOL

5) It picks-up all kinds of static and other interference that is ignored by the limiter and FM detector of a real FM radio, because it has an AM detector.

maybe thats one drawback, but that wont stop me from going with superregen.

6) For it to be sensitive you must fiddle with its sensitivity control (amount of positive feedback).

I'd rather waste 10 minutes doing that than 10 minutes finding the simplest transistor superhet receiver.

7) The super-regen's audio output fades away and gets very difficult to tune and re-tune as its tuned signal gets weaker. That's why Mstechca needs an audio amplifier with a lot of gain. Its noise level stays the same. A real FM radio's audio level stays the same as its tuned signal weakens (but its noise level increases).

I prefer to hear what I receive, not fiddle for nothing.

8) A real FM radio's noise level decreases with increased signal strength, because it has lots of gain and limiting. So a signal that is only just a little stronger than what is barely detectable is heard without noise (quieting).

A superregen could qualify.

There are probably more things wrong with a simple super-regen that I can't think of.

I'm still not walking away from a superregen yet.

 

[anthony123]

Hi everybody.. Here i'm againg hehehehehehehe..!! What are your opinion about TDA1083..?